While working I woke up at 5:30 so I could get myself ready before dealing with the kids, and still be at work by 7:30am. Then had kid/family stuff till 8:30 or 9pm, and any tv/down time from 9-10ish. So sleep was 10ish to 5:30am. But I had twice weekly conference calls with overseas teams - they were at 5-5:30am, and 10-10:45pm. (These after hour teleconferences were a contributing factor to my wanting to retire.)
Until recently, even though I was retired, I still had kid responsibilities - needed to get them out the door to school for their super early bells (first bell at 7:25am) - by bus or my car. So I would get up at 5:30am. I combined that early up and out with taking the dog to the beach. I fell in love with early morning (sunrise) beach walks with the dog. The big change was I didn't have as much to do, household wise, since I could get it done during the day. I found myself going to bed earlier. 9ish.
Now the kids are out of the house. (Youngest is a freshman in college.) I still wake up at 5:30. I set my alarm, but usually wake up right before it's time. If I don't want to wake up, I go back to sleep. But usually I get up, go to the beach by 6:15 or 6:30 and have that wonderful walk watching sunrise surfers. But - with no kids to worry about - I find myself heading up to bed around 8:30 and sound asleep by 9pm. Woohoo I'm the life of the party. Fortunately we have a DVR so I can watch the primetime tv shows the next day.
I sleep well and about 8 1/2 hours per night. Sometimes I wake up to pee, sometimes I don't. I never have a problem falling back asleep unless something is worrying me.